Structures and Thermodynamics of MgO/SiO Interfaces

Oschinski, Hedda; Kesuma, Inez; Gebensleben, Tim; Becker, J. A.

doi:10.1021/acs.jpcc.9b08608

Cited by 3 publications

(3 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results are given in Table 1. It should be noted that the entire discussion is based on single-point calculations of geometry-optimized structures reflecting a formal situation at T = 0 K. However, this does not take into account the vibrational zero point energies, excess entropies, and excess heat capacities of the surfaces that have been studied for simpler surfaces such as MgO(110) [77]. Note that the mass equilibrium at T = 0 K is orthorhombic and not cubic [70].…”

Section: Ab-initio Calculations and Theoretical Considerationsmentioning

confidence: 99%

On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crystal Studies of Optoelectronic Properties

et al. 2021

Self Cite

View full text Add to dashboard Cite

Hybrid perovskite materials are one of the most promising candidates for optoelectronic applications, e.g., solar cells and LEDs, which can be produced at low cost compared to established materials. Although this field of research has seen a huge upsurge in the past decade, there is a major lack in understanding the underlying processes, such as shape-property relationships and the role of defects. Our aerosol-assisted synthesis pathway offers the possibility to obtain methylammonium lead bromide (MAPbBr3) microcrystals from a liquid single source precursor. The differently shaped particles are aligned on several substrates, without using a directing agent or other additives. The obtained particles show good stability under dry conditions. This allows us to characterize these materials and their pure surfaces at the single-crystal level using time- and spatially resolved methods, without any influences of size-dependent effects. By optimizing the precursor for the aerosol process, we were able to eliminate any purification steps and use the materials as processed. In addition, we performed theoretical simulations to deepen the understanding of the underlying processes in the formation of the different crystal facets and their specific properties. The model system presented provides insights into the shape-related properties of MAPbBr3 single crystals and their directed but ligand-free synthesis.

show abstract

Section: Ab-initio Calculations and Theoretical Considerationsmentioning

confidence: 99%

On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crystal Studies of Optoelectronic Properties

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Also the external quantum efficiency was enhanced from 62.5% to 89.5% upon illumination from 350 to 600 nm light. MgO has advantages of high optical transparency, superior chemical inertness, good thermal stability, and very high bandgap of 7.8 eV. , The MgO layer has been applied to passivate the surface defects of ZnO and TiO 2 , suppressing the interface/surface recombination and reducing the dark current of the devices. , In this study, NiO and MgO layers were inserted into p-Si/n-ZnO HPDs to increase UV response and suppress visible response. The effects of NiO and MgO insertion layers on HPDs were studied in detail.…”

Section: Introductionmentioning

confidence: 99%

“…MgO has advantages of high optical transparency, superior chemical inertness, good thermal stability, and very high bandgap of 7.8 eV. 34,35 The MgO layer has been applied to passivate the surface defects of ZnO and TiO 2 , suppressing the interface/ surface recombination and reducing the dark current of the devices. 36,37…”

Section: Introductionmentioning

confidence: 99%

Enhancement of UV Response and Suppression of Visible Response of p-Si/n-ZnO Heterojunction Photodiodes via NiO and MgO Insertion Layers

Hwang

Liao

2020

J. Phys. Chem. C

View full text Add to dashboard Cite

Nickel oxide (NiO) and magnesium oxide (MgO) thin films were inserted into p-Si/n-ZnO heterojunction photodiodes (HPDs), and their mechanisms in enhancing ultraviolet (UV) response and suppressing visible response were studied. The insertion of the MgO layer greatly reduced the leakage current of the HPDs due to the passivation of surface states in ZnO and hence enhanced the rectification ratio from 258.7 to 3769.2 by 14.6-times. HPDs with the NiO layer exhibited the highest UV response and photocurrent for all HPDs because NiO absorbs UV light. HPDs with the MgO layer demonstrated the least visible response and dark current. Among all of the HPDs, those with the NiO layer exhibited the largest UV-to-visible rejection ratio, while those with the MgO layer had the highest photo-to-dark current ratio and detectivity. The UV-to-visible rejection ratio was greatly enhanced from 101.1 to 652.3 by 6.4-times after the insertion of the NiO layer, and the photo-to-dark current ratio was enhanced from 3.3 × 102 to 4.5 × 104, by 136.4-times, after the insertion of the MgO layer. The HPDs with NiO insertion layer presented the fastest transient response, and those with MgO insertion revealed the slowest transient response due to the carrier trapping. Related mechanism for the improvements was elucidated by the band diagram.

show abstract

Ab initio study of surfaces of lead and tin based metal halide perovskite structures

Kuper,

Jörg August

2024

Zeitschrift Für Physikalische Chemie

View full text Add to dashboard Cite

Hybrid perovskite materials, known for their potential in cost-effective optoelectronic applications, face a knowledge gap in crucial areas, particularly the atomic-level properties of the surface. This study addresses this challenge by refining ab initio methods for characterizing surface structures of cubic methylammonium lead bromide and methylammonium tin bromide (MAMeBr3 with Me = Sn, Pb), avoiding superficial restrictions in atomic movement during geometry optimization. The resulting structures confirmed nearly random MA+ molecule alignment, comparable to real-world experimental conditions. Calculating surface energies for these structures with crystal orientations {100} and {110}, each with different terminations, provides valuable insights into structural properties. Using a carefully chosen thermodynamic reference state, mimicking experimental conditions enables a thermodynamic discussion and facilitates the modulation of the MeBr2 component’s chemical potential. This modulation, in turn, allows for the prediction of crystal morphologies, as illustrated by Wulff’s construction. This approach establishes a crucial link between theoretical predictions and experimental conditions, shedding light on the complexities of hybrid perovskite materials.

show abstract

Structures and Thermodynamics of MgO/SiO Interfaces

Cited by 3 publications

References 74 publications

On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crystal Studies of Optoelectronic Properties

On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crystal Studies of Optoelectronic Properties

Enhancement of UV Response and Suppression of Visible Response of p-Si/n-ZnO Heterojunction Photodiodes via NiO and MgO Insertion Layers

Ab initio study of surfaces of lead and tin based metal halide perovskite structures

Contact Info

Product

Resources

About